1. Field of the Invention
The present invention relates to a press section of a machine for producing a fibrous web, e.g., a paper or cardboard web, having at least two nips extended in length in a web travel direction. Each of the at least two nips is formed between a revolving flexible press belt of a shoe press unit and a counterpart face. The flexible press belt can be pressed against the counterpart face by at least one press shoe associated with the respective shoe press unit. The respective nip length may be determined at least substantially by the press shoe length, measured in the web travel direction, of the associated shoe press unit.
2. Discussion of Background Information
The advantages of extended nip presses known in the art include, inter alia, that the nip is no longer substantially linear but instead is two-dimensional. In this manner, the still-wet fibrous web is exposed to pressing pressure over a longer distance and, thus, is more intensively dewatered. Further, the onset of pressure in the nip is no longer sudden. Instead, the pressure can be brought continuously, e.g., from a low value to a high value, thus, avoiding a risk that the fibrous web will become crumpled in the nip.
In previous conventional press sections similar in general to the type described above, the shoe press units associated with the various nips have identical press shoes, or press shoes of equal length. Thus, the press section includes nips of the same length.